St. Augustine grass

ABSTRACT

A perennial St. Augustine grass having outstanding dark green color, rapid lateral spread, a semi-dwarf growth habit, and a medium level of flowering shoot production. This variety has good gray leafspot resistance throughout the year and is cold tolerant.

SUMMARY OF THE VARIETY

This invention relates to a new and distinct perennial St. Augustine grass selected from the progeny of an open pollinated purple stigma diploid parent Ea611081. This purple stigma genotype was labeled 615866 and propagated vegetatively by stolons to provide planting stock for studying performance and making comparisons to present commercial varieties.

Genotype 615866 has a wide leaf blade, a short leaf length, and an outstanding dark green color. These characteristics along with the rapid spread, its medium level of flowering shoot production, its good gray leafspot (Piricularia grisea) resistance, and its cold tolerance can be used to distinguish 615866 from other St. Augustine grasses.

BRIEF DESCRIPTION OF THE ILLUSTRATIONS

FIG. 1 is a photograph of 615866 St. Augustine turf showing generally the characteristics of this new grass;

FIG. 2 shows the leaves and stem of a 615866 St. Augustine grass plant;

FIG. 3 shows a spike of a 615866 St. Augustine grass plant; and

FIG. 4 shows florets of a 615866 St. Augustine grass plant.

DETAILED DESCRIPTION OF THE VARIETY

Genotype 615866 possesses a Munsell color designation 7.5 GY 4/4 ^(1/) and is characterized by compressed and branched culms. The leaf blades are relatively short, averaging 44.8 mm. long, but are very coarse, averaging 7.66 mm. wide. These characteristics can be used to distinguish 615866 from both the dwarf and non-dwarf St. Augustine grasses. The average internode length is 35.0 mm., thus allowing this semi-dwarf to have a vigorous lateral spread. Genotype 615866 has a purple stigma color and an unreduced chromosome number of 18.

Total soluble salts measured in micromhos/cm. specific conductance using a Beckmann Solu-Bridge will allow differentiation between 615866 and other St. Augustine grasses. The average reading for 615866 was 146.1 micromhos/cm. The chromosome numbers, stigma colors, morphological measurements of 615866 and other St. Augustine grasses are compared in Tables 1, 2 and 3.

                  Table 1                                                          ______________________________________                                         Chromosome Numbers and Stigma Colors                                           of 615866 and other St. Augustine grasses                                      ______________________________________                                                        Chromosome Number                                                                              Stigma                                          Selection/Variety                                                                             (Unreduced).sup.2                                                                              Color                                           ______________________________________                                         615866         18              Purple                                          45176          18              "                                               73176          18              "                                               Ea611081       18              "                                               Floratine      27              "                                               Bitter Blue    27              "                                               Texas Common   18              White                                           ______________________________________                                          .sup.1 The Munsell designated color is of plant material grown in the          greenhouse. The color is subject to variation depending upon the               environmental conditions under which the grass is grown.                       .sup.2 Chromosome Number determinations made on pollen mother cells.     

                  Table 2                                                          ______________________________________                                         Comparative Leaf Blade Length, Width and Internode Length                      for 615866 and Other St. Augustine grasses                                     ______________________________________                                                    Leaf Blade  Leaf Blade Internode                                    Selection/ Length      Width      Length                                       Variety    (mm.).sup.1 (mm.).sup.2                                                                               (mm.).sup.3                                  ______________________________________                                         615866     44.8 ± 11.6                                                                             7.66 ± 0.72                                                                            35.0 ± 7.7                                45176      44.2 ± 11.8                                                                             6.04 ± 0.89                                                                            22.8 ± 3.8                                73176      33.4 ±  7.3                                                                             5.86 ± 1.09                                                                            10.8 ± 2.2                                Ea611081   78.4 ± 33.3                                                                             7.12 ± 1.38                                                                            36.0 ± 7.4                                Floratine  82.8 ± 25.9                                                                             7.81 ± 2.46                                                                            36.3 ± 7.3                                Bitter Blue                                                                               105.2 ± 31.8                                                                            8.55 ± 1.25                                                                            38.3 ± 8.7                                Texas Common                                                                              45.0 ± 16.8                                                                             6.48 ± 0.85                                                                            34.0 ± 4.2                                LSD 5%     12.1        .71        4.0                                          ______________________________________                                          .sup.1 All plant material grown unclipped in greenhouse.                       .sup.2 Measurements recorded 15 millimeters above leaf collar.                 .sup.3 Measurements recorded between third and fourth internodes.        

                  Table 3                                                          ______________________________________                                         Specific Conductance Measurements of 615866                                    and Other St. Augustine grasses                                                ______________________________________                                                           Specific Conductance                                         Selection/Variety (micromhos/cm.).sup.1                                        ______________________________________                                         615866            146.1                                                        45176             104.1                                                        73176             107.3                                                        Ea611081          132.3                                                        Bitter Blue       190.2                                                        Texas Common      122.8                                                        ______________________________________                                          .sup.1 Measurements were made on a six centimeter stem section.          

The characteristic growth habit can be used to distinguish 615866 from the dwarf St. Augustine grasses 73176 and 45176, and the more upright growing types Bitter Blue and Texas Common. In addition, fresh weight clipping yields can be used to distinguish 615866 from the two dwarf selections and Ea611081. This information is illustrated in Tables 4 and 5. In Table 6 it can be seen that the leaf texture of 615866 is similar to that of the coarser types Bitter Blue and Texas Common thus differentiation in these cases must be based on the lower growth habit of 615866.

                  Table 4                                                          ______________________________________                                         Comparative Growth Habit Averages for 615866 and Other                         St. Augustine grasses at Apopka, Florida, and Katy, Texas                      ______________________________________                                                   Growth Habit.sup.1                                                   Selection/  Florida    Texas      Florida                                      Variety     1971       1971       1972                                         ______________________________________                                         615886      3.4        4.1        3.0                                          45176       2.6        2.5        2.1                                          73176       2.4        2.5        1.6                                          Ea611081    3.4        4.0        3.2                                          Bitter Blue 4.4        4.5        3.7                                          Texas Common                                                                               --         --         --                                                       --         --          .2                                          ______________________________________                                          .sup.1 Rating 1 - low growing, 5- upright growing                        

                  Table 5                                                          ______________________________________                                         Fresh weights of Clippings Removed From Plots of 615866                        and Other St. Augustine grasses                                                ______________________________________                                                    Fresh Weights                                                       Selection/ (gms/.48m × 1.52 m plot)                                      Variety    July        August     September                                    ______________________________________                                         615866     24.7 ± 9.1                                                                              40.0 ± 15.1                                                                            38.3 ± 8.7                                45176      6.3 ± 2.1                                                                               19.7 ± 10.0                                                                            13.7 ± 6.4                                73176      3.0 ± 1.7                                                                                6.0 ±  3.6                                                                             7.7 ± 2.9                                Ea611081   36.7 ± 12.9                                                                             74.0 ± 12.5                                                                            45.0 ± 8.2                                Bitter Blue                                                                               22.3 ± 9.9                                                                              43.7 ± 15.3                                                                            29.7 ± 4.9                                LSD 5%     16.6        21.8       11.0                                         ______________________________________                                    

                  Table 6                                                          ______________________________________                                         Comparative Texture Averages for 615866 and Other St.                          Augustine grasses at Apopka, Florida, and Katy, Texas                          ______________________________________                                                   Texture.sup.1                                                        Selection/  Florida    Texas      Florida                                      Variety     1971       1971       1972                                         ______________________________________                                         615866      1.9        1.7        2.3                                          45176       2.7        2.1        3.0                                          73176       2.9        2.5        3.1                                          Ea611081    1.7        2.0        2.3                                          Bitter Blue 1.4        1.5        2.0                                          Texas Common                                                                               --         1.1        --                                           LSD 5%      --         --          .2                                          ______________________________________                                    

Genotype 615866 has an outstanding dark green color and a medium level of flowering shoot production. Field observations have shown that 615866 has the fastest rate of cover of any St. Augustine grass tested including Ea611081. The observations of color and rate of cover used in combination can allow distinction of 615866 from Ea611081. This information is illustrated in Tables 7, 8 and 9.

                  Table 7                                                          ______________________________________                                         Comparative Color Averages for 615866 and Other St.                            Augustine grasses at Apopka, Florida, and Katy, Texas                          ______________________________________                                                   Color.sup.1                                                          Selection/  Florida    Texas      Florida                                      Variety     1971       1971       1972                                         ______________________________________                                         615866      9.4        8.9        8.0                                          45176       8.7        9.3        7.9                                          73176       8.9        9.3        8.1                                          Ea611081    8.7        8.7        7.8                                          Bitter Blue 9.1        8.7        7.8                                          Texas Common                                                                               --         8.8        --                                           LSD 5%      --         --          .2                                          ______________________________________                                          .sup.1 Rating 1 - lightest green, 10 - darkest green                     

                  Table 8                                                          ______________________________________                                         Comparative Ratings of Average Flowering Shoot Production                      of 615866 and Other St. Augustine grasses at Apopka,                           Florida, and Katy, Texas                                                       ______________________________________                                                    Average Flowering Shoot Production.sup.1                            Selection    Texas          Florida                                            Variety      9/17/71        6/15/72                                            ______________________________________                                         615966       1              2.3                                                45176        3              2.3                                                73176        0               .7                                                Ea611081     0              2.0                                                Bitter Blue  0              1.3 -Texas Common 3 --                             LSD 10%      --             1.0                                                ______________________________________                                          .sup.1 Rating 0 - no flowering shoot production, 5 - heavy flowering shoo      production.                                                              

                  Table 9                                                          ______________________________________                                         Relative Comparison of Percent Turf Cover of 615866 and                        Other St. Augustine grasses at Apcpka, Florida                                 ______________________________________                                         Selection/                                                                               Average Percent Area Covered.sup.1                                   Variety   2/15/72   4/3/72   5/1/72                                            ______________________________________                                         615866    53        60       97    100                                         45176     37        47       60    93                                          73176     40        47       67    93                                          Ea611081  57        60       87    97                                          Bitter Blue                                                                              47        53       70    97                                          LSD 5%     8        10       15    N.S.                                        ______________________________________                                          .sup.1 Initial planting made 12/1/71                                     

Genotype 615866 has a lower percent gray leafspot (Piricularia grisea) infestation throughout the whole year than any selection other than the very leafspot resistant dwarf 73176. This observation can be used to distinguish 615866 from other less resistant selections such as Bitter Blue and Texas Common. This information is given in Table 10.

                                      Table 10                                     __________________________________________________________________________     Comparative Gray Leafspot (Piricularia Grisea) Resistance of                   7615866 and Other St. Augustine grasses at Apopka, Florida and                 Katy, Texas.                                                                   __________________________________________________________________________             Percent Gray Leafspot                                                  Selection/                                                                             Florida                                                                             Texas                                                             Variety 6/28/71                                                                             4/31/71                                                                           6/29/71                                                                               7/31/71                                                                             9/2/71                                                                              9/17/71                                       __________________________________________________________________________     615866  20   10   10   10   10    0                                            45176   20   20   30   10   20   30                                            73176   20   10   20   10    5    0                                            Ea611081                                                                               20   10   30   20   10   30                                            Bitter Blue                                                                            40   90   10   10   10   20                                            Texas Common                                                                           --   10   60   20   30   20                                            __________________________________________________________________________

The cold tolerance of 615866 and other St. Augustine grasses is shown in Table 11. The cold tolerance of this genotype allows differentiation from other less tolerant St. Augustine grasses under sub-zero (centigrade) stress.

                  Table 11                                                         ______________________________________                                         Comparative Cold Damage from Below Zero (centigrade)                           Temperature of 615866 and Other St. Augustine grasses in                       Apopka, Florida and Katy, Texas                                                ______________________________________                                                   Percent Cold Damage.sup.1                                            Selection/  Texas      Florida 1973                                            Variety     1972       Test - A.sup.2                                                                            Test - B.sup.3                               ______________________________________                                         615866       0          5         27.5                                         45176       95         60         47.5                                         73176       99         40         35.0                                         Ea611081    99         15         50.0                                         Bitter Blue 20          5         52.5                                         Texas Common                                                                                0         --         --                                           ______________________________________                                          .sup.1 Cold damage as measured by percent stolons killed.                      .sup.2 Test - A, Two year old sod.                                             .sup.3 Test - B, One year old sod.                                        

What is claimed and desired to be secured by Letters Patent is:
 1. A St. Augustine grass, substantially as herein illustrated and described. 